This invention relates to processes for making novel inulin products, and food products containing such inulin products.
Inulin, which has been extracted from plants for nearly 100 years with difficulty, belongs to the polysaccharide family of compounds. Inulin is composed of a mixture of polysaccharides having various molecular weights or degrees of polymerization (DP). In general, inulin consists of fructose units with xcex2 1-2 bonds and end in a glucose unit. The addition or subtraction of fructose units affects inulin""s molecular weight or degree of polymerization (DP). Typical inulin properties are set forth in Table 1 below.
Inulin is the main carbohydrate in a variety of plants. Table 2 lists common inulin sources and the inulin concentrations therein.
Chicory continues to be grown extensively throughout Europe, and its many varieties are harvested and processed into an assortment of products from salad greens and cattle feed to fructose and recently to inulin. Because of its ease of cultivation and harvesting, chicory has become the principal source of inulin today.
As inulin comes from the field in the chicory plant, its molecular weight depends on many factors such as time of planting, time of harvest, amount of stress, variety type, amount of time which elapsed between harvest and processing, amount of damage at harvest and other factors.
Today, inulin is approved for use as a food additive by the governments of nine European countries (Belgium, Denmark, France, Luxembourg, Netherlands, Portugal, Spain, Sweden, and Switzerland) and Japan, and its applications are varied.
Despite the approval of inulin as a food additive in many countries, the use of inulin has been limited, because, among other things, of the limited solubility and/or miscibility of inulin in water at ambient temperature, for example, at temperatures from about 10xc2x0 C. to about 25xc2x0 C.
One publication reports the solubility in water of inulin derived from chicory roots to be less than about 3% (% weight/volume) at 30xc2x0 C., and less than about 5% (% weight/volume) at 40xc2x0 C. See E. Berghofer et al., PILOT-SCALE PRODUCTION OF INULIN FROM CHICORY ROOTS AND ITS USE IN FOODSTUFFS, CROPS, Elsevier Science Publishers, B.V., A. Fuchs, Editor, 1993 (pp. 77-84).
Caloric concerns have long played a significant role in the food choice of the U.S. public, and low calorie foods have been popular for years. Foods of this category have been dominated by those products where fructose and sucrose have been replaced by an artificial sweetener which can add sweetness without the caloric impact. In particular, the success of the artificial sweeteners such as saccharin, aspartame and more recently sucralose, should be noted.
Most artificial sweeteners, such as saccharin and aspartame, have 180 to 300 times the sweetness of an equivalent dose of sucrose. Sucralose is a sweetener 600 times sweeter than sugar. Therefore, food processors will obviously use a much lower volume of these artificial sweeteners in their low calorie foods than the volume of sugar which they replace. With dry goods (such as baked products), food processors are forced to xe2x80x9cback fillxe2x80x9d the volume of the removed sugar which the artificial sweeteners do not replace. This back fill product is referred to as a xe2x80x9cbulking agent.xe2x80x9d Bulking agents are found in a variety of products, including chewing gums, confectioneries, baking mixes, meat products, and packets containing the artificial sweetener in amounts equivalent of one or more teaspoons of sugar. The optimal bulking agents should bring the physical and chemical characteristics of sugar back to the food without adding back calories or contributing significantly to product cost.
Bulking agents are evaluated against the following criteria:
1. Significantly fewer calories than sucrose, glucose or fructose.
2. Physical and chemical properties that match those of sucrose in all food applications
3. Mouthfeel comparable to sugar.
4. Freedom from adhesion to lips and tongue.
5. Freedom from toothpack (freedom from packing into crowns of teeth).
6. Preferrably, demonstrate existence of secondary health benefits
7. No negative side effects and completely safe at reasonable levels of consumption
8. In the dry product, freedom from caking and clumping.
9. In the wet product no settling out or fractionation upon standing.
More specifically, in order to effectively replace sucrose and fructose and their organoleptic qualities, potential bulking agents must display the following characteristics:
Safe
Stable
Low calorie
Minimal gastrointestinal side effects
Low cost
No off-flavors
High solubility
Low viscosity
Crystalline
Ability to brown
Protein/Starch interactions similar to sucrose
A major obstacle to the use of inulin as a bulking agent in foodstuffs despite its many advantages is its rather low solubility in water at ambient temperatures.
Another major obstacle to the use of inulin as a bulking agent is the presence of various amounts of glucose and fructose, which are naturally contained therein, and which have made inulin difficult to dry and difficult to handle and store. In the drying of inulin, the presence of glucose and fructose, which are hygroscopic, interferes with the drying process, unless there is a large proportion of high molecular weight inulin which dries more readily than the lower molecular weight inulin compounds. Even after drying, the hygroscopicity of glucose and fructose tends to reintroduce moisture into the product.
In the case of granular or dry inulin products, the hygroscopic activity of glucose and fructose tends to cause undesirable caking and clumping. Due to the caking and clumping the granular or dry inulin products containing glucose and fructose are difficult to handle, store, and blend.
In addition, most inulin products used as bulking agents with artificial sweeteners heretofore have contained significant amounts of fructose and glucose and also contained high molecular weight inulin compounds, for example, molecular weights above 2288. When such inulin products are taken by mouth, there is a formation of sticky, hard substance in the mouth caused by the insolubility of such high molecular weight inulin in the saliva at body temperatures. This sticky substance may adhere to the lips and tongue, and may pack on the crowns of the consumer""s teeth. In some cases, the sticky substance forms a crusty insoluble mass in the mouth which must be chewed in order to break up.
In the case of liquid inulin products, there is tendency for higher molecular weight inulin fractions to xe2x80x9csettle out,xe2x80x9d or fractionate, upon standing which has made it difficult to provide a satisfactory liquid product.
Inulin comprises polysaccharides, fragile polymers, which are difficult to extract by classical prior methods. European Patent 787 745 illustrates one method for extraction of inulin from Jerusalem artichokes using the classical sugarbeet extraction, and then clarifying the inulin rich extraction liquid by ultrafiltration. Silver U.S. Pat. No. 5,456,893 discloses a process and apparatus for extracting inulin in a manner which does not degrade the inulin or allow the inulin to be broken down.
Accordingly, it is an object of the invention to design novel products of inulin which have improved properties for use in foodstuffs, in particular, improved solubility at ambient temperatures.
It is a further object of the invention to provide novel products of inulin characterized by reduced hygroscopicity.
It is another object of the invention to design products of inulin that can be used as bulking agents without a tendency to cake and clump.
It is still another object of the invention to design products of inulin that can be used as bulking agents without formation of undesirable sticky substances in the mouth.
It is still another object of the invention to design products of inulin that can be used as bulking agents that can be mixed with water without formation of sticky clumps or lumps.
It is another object of the invention to design water base products containing inulin which have a reduced tendency to fractionate or settle out upon standing.
It is yet another object of the invention to provide novel processes for separating inulin into desirable products that have improved water solubility and/or water miscibility at ambient temperatures.
It is still yet another object of the invention to provide novel processes for separating high molecular weight fractions of inulin which are suitable as, for example, ingredients for food, or as fat substitutes.
Other objects of the invention will be apparent from the following description and accompanying drawing.